1 He mumbled unintelligibly and looked abashed.
2 Everyone was watching Zhang Kou and murmuring unintelligibly from time to time.
3 The foreigners spoke unintelligibly.
4 As a result, there would be no automatic announcements during the whole ride. Instead, the captain had to mumble unintelligibly through the speakers.
5 Missing is a power that can draws one's tears unintelligibly.
6 He points at the people in the queue and speaks so unintelligibly that only I can understand him.